txhawm rau tsim kom muaj qhov zoo ntawm ntau cov khoom noj khoom haus, cov tshuaj xantoprotein rau cov protein yog siv. Lub xub ntiag ntawm aromatic amino acids nyob rau hauv lub compound yuav muab ib tug zoo xim hloov rau cov qauv kuaj.
Y Yuav ua li cas yog protein
Nws tseem hu ua cov protein, uas yog cov khoom siv hauv tsev rau lub cev muaj sia. Proteins tswj cov leeg nqaij, kho cov ntaub so ntswg raug mob thiab tuag ntawm ntau yam kabmob, txawm tias nws yog plaub hau, tawv nqaij lossis ligaments. Nrog rau lawv cov kev koom tes, cov qe ntshav liab raug tsim, ua haujlwm ntawm ntau cov tshuaj hormones thiab cov hlwb ntawm lub cev tiv thaiv kab mob.
Nov yog ib qho molecule complex, uas yog ib tug polypeptide nrog ib tug loj dua 610 3d altons. Cov qauv protein yog tsim los ntawm cov amino acid residues nyob rau hauv ntau qhov ntau, txuas nrog peptide daim ntawv cog lus.
Protein structure
Ib qho tshwj xeeb ntawm cov tshuaj no nyob rau hauv kev sib piv nrog qis molecular hnyav peptides yog lawv cov qauv tsim spatial peb-dimensional, txhawb los ntawm kev cuam tshuam los ntawm kev sib txawv.degree ntawm attraction. Proteins muaj plaub theem qauv. Txhua tus muaj nws tus yam ntxwv.
Lub koom haum tseem ceeb ntawm lawv cov molecules yog raws li cov amino acid ib ntus, cov qauv uas tau lees paub los ntawm xantoprotein cov tshuaj tiv thaiv rau cov protein. Xws li cov qauv yog ib ntus rov ua dua peptide daim ntawv cog lus -HN-CH-CO-, thiab sab saw radicals hauv aminocarboxylic acids yog xaiv ib feem. Nws yog lawv tus uas txiav txim siab txog cov khoom ntawm cov khoom nyob rau hauv lub neej yav tom ntej.
Cov qauv protein tseem ceeb yog suav tias muaj zog txaus, qhov no yog vim muaj kev sib cuam tshuam covalent muaj zog hauv peptide bonds. Kev tsim ntawm qib tom ntej tshwm sim nyob ntawm cov cim tau tsim nyob rau theem pib.
Kev tsim ntawm cov qauv thib ob yog ua tau vim qhov sib tw ntawm cov amino acid ib ntus mus rau hauv ib lub kauv, nyob rau hauv uas hydrogen bonds yog tsim los ntawm cov lem.
Qib theem ntawm lub koom haum ntawm cov molecule yog tsim thaum ib feem ntawm lub helix yog superimposed rau lwm cov fragments nrog tshwm sim ntawm txhua yam kev sib raug zoo ntawm lawv, nrog ib tug hydrogen, disulfide, covalent los yog ionic compound. Qhov tshwm sim yog koom nrog hauv daim ntawv ntawm globules.
Qhov kev npaj ntawm cov txheej txheem tertiary nrog kev tsim cov tshuaj sib txuas ntawm lawv ua rau tsim cov ntawv kawg ntawm cov molecule lossis qib plaub.
Amino acids
Lawv txiav txim siab cov khoom siv tshuaj ntawm cov protein. Muaj txog 20 lub ntsiab amino acids,muaj nyob rau hauv muaj pes tsawg leeg ntawm polypeptides nyob rau hauv sib txawv sequences. Qhov no kuj suav nrog tsawg aminocarboxylic acids nyob rau hauv daim ntawv ntawm hydroxyproline thiab hydroxylysine, uas yog derivatives ntawm peptides yooj yim.
Raws li lub cim ntawm xantoprotein cov tshuaj tiv thaiv ntawm kev lees paub cov protein, muaj cov amino acids ib tus neeg ua rau muaj kev hloov pauv ntawm cov xim ntawm cov reagents, uas qhia txog qhov muaj cov qauv tshwj xeeb hauv lawv cov muaj pes tsawg leeg.
Raws li nws tau muab tawm, lawv yog tag nrho cov carboxylic acids, uas cov hydrogen atom tau hloov los ntawm ib pawg amino.
Ib qho piv txwv ntawm cov qauv ntawm cov molecule yog cov qauv qauv ntawm glycine (HNH- HCH- COOH) raws li qhov yooj yim amino acid.
Hauv qhov no, ib qho ntawm cov hydrogens CH2- carbon tuaj yeem hloov tau los ntawm cov radical ntev dua, suav nrog lub nplhaib benzene, amino, sulfo, carboxy pawg.
xantoprotein cov tshuaj tiv thaiv txhais li cas
Txoj kev sib txawv yog siv rau kev txheeb xyuas cov protein zoo. Cov no suav nrog cov tshuaj tiv thaiv:
- biuret nrog ntshav xim;
- ninhydrin los tsim cov tshuaj xiav-violet;
- formaldehyde nrog liab staining;
- Foil nrog grey-dub sedimentation.
Thaum ua tiav txhua txoj hauv kev, muaj cov proteins thiab muaj qee cov pab pawg ua haujlwm hauv lawv cov molecule raug pov thawj.
Muaj cov tshuaj xantoprotein rau cov protein. Nws tseem hu ua Mulder test. Nws hais txog cov xim xim ntawm cov proteins, hauvuas yog aromatic thiab heterocyclic amino acids.
Ib yam ntawm qhov kev sim no yog cov txheej txheem ntawm nitration ntawm cyclic amino acid residues nrog nitric acid, tshwj xeeb, ntxiv ntawm ib pab pawg nitro rau lub nplhaib benzene.
Qhov tshwm sim ntawm cov txheej txheem no yog tsim los ntawm nitro compound, uas ua rau nag. Qhov no yog lub cim tseem ceeb ntawm xantoprotein cov tshuaj tiv thaiv.
Dab tsi amino acids txiav txim siab
Tsis yog tag nrho cov aminocarboxylic acids tuaj yeem kuaj tau siv qhov kev sim no. Lub ntsiab feature ntawm xantoprotein cov tshuaj tiv thaiv ntawm cov protein paub yog muaj lub nplhaib benzene los yog heterocycle nyob rau hauv cov amino acid molecule.
Los ntawm cov protein aminocarboxylic acids, ob lub aromatic acids cais, uas muaj ib pawg phenyl (hauv phenylalanine) thiab hydroxyphenyl radical (hauv tyrosine).
Cov tshuaj tiv thaiv xantoprotein yog siv los txiav txim siab heterocyclic amino acid tryptophan, uas muaj cov tshuaj tsw qab indole nucleus. Lub xub ntiag ntawm cov tebchaw saum toj no hauv cov protein muab cov yam ntxwv hloov xim ntawm qhov ntsuas nruab nrab.
Yuav ua li cas thiaj siv tau
Txhawm rau ua tiav cov tshuaj xantoprotein, koj yuav tsum tau npaj 1% tov ntawm qe lossis zaub protein.
Feem ntau siv lub qe qaib, uas tawg ntxiv kom cais cov protein ntawm lub qe. Yuav kom tau txais kev daws, 1% protein yog diluted hauv kaum npaug ntawm cov dej huv. Tom qab dissolving cov protein, lub resulting kua yuav tsum tau lim los ntawm ob peb txheej ntawm gauze. Cov tshuaj no yuav tsum muab cia rau hauv qhov chaw txias.
Koj tuaj yeem nqa tawm cov tshuaj tiv thaiv nrog zaub protein. Txhawm rau npaj cov tshuaj, cov hmoov nplej yog siv rau hauv tus nqi ntawm 0.04 kg. Ntxiv 0.16 l dej huv. Cov khoom xyaw yog tov nyob rau hauv ib lub hwj, uas yog muab tso rau 24 teev nyob rau hauv ib qhov chaw txias nrog ib tug kub ntawm txog +1 ° C. Tom qab ib hnub, cov tshuaj yog shaken, tom qab uas nws yog lim ua ntej nrog paj rwb ntaub plaub, thiab ces nrog ib daim ntawv pleated lim. Lub resulting kua yog khaws cia nyob rau hauv ib tug txias qhov chaw. Hauv cov kev daws teeb meem no, feem ntau yog ib feem ntawm albumin.
Txhawm rau ua tiav cov tshuaj tiv thaiv xantoprotein, concentrated nitric acid yog siv los ua lub ntsiab reagent. Ntxiv cov tshuaj reagents yog ib qho kev daws ntawm 10% sodium hydroxide lossis ammonia, cov tshuaj gelatin thiab tsis yog cov tshuaj phenol.
Methodology
Nyob rau hauv lub raj kuaj huv ntxiv 1% tov ntawm qe protein los yog hmoov nplej hauv ib qho nyiaj ntawm 2 ml. Txog 9 tee ntawm cov concentrated nitric acid ntxiv rau nws kom tsis txhob muaj cov flakes poob. Cov txiaj ntsig sib xyaw yog rhuab, vim li ntawd, cov nag lossis daus tig daj thiab maj mam ploj mus, thiab nws cov xim nkag mus rau hauv kev daws teeb meem.
Thaum cov kua txias txias, txog 9 tee ntawm cov ntsiab lus sodium hydroxide tau ntxiv rau hauv lub raj kuaj raws phab ntsa, uas yog qhov ntau tshaj rau cov txheej txheem. Cov tshuaj tiv thaiv ntawm qhov nruab nrab ua alkaline. Cov ntsiab lus hauv lub raj tig txiv kab ntxwv.
Ntse
Vim xantoprotein yog hu ua cov tshuaj tiv thaiv zoo rau cov proteins hauv qablos ntawm qhov kev txiav txim ntawm nitric acid, tom qab ntawd qhov kev ntsuam xyuas yog ua nyob rau hauv lub fume hood. Ua raws li tag nrho cov kev ntsuas kev nyab xeeb thaum ua haujlwm nrog cov tshuaj ua kom muaj zog.
Thaum lub sijhawm cua sov, cov ntsiab lus ntawm lub raj yuav raug tshem tawm, uas yuav tsum tau coj mus rau hauv tus account thaum kho nws nyob rau hauv lub tuav thiab xaiv ib qho inclination.
Kev noj cov tshuaj nitric acid thiab sodium hydroxide tsuas yog yuav tsum tau ua nrog lub iav pipette thiab roj hmab qhov muag, nws yog txwv tsis pub ntaus los ntawm qhov ncauj.
Sib piv cov tshuaj tiv thaiv nrog phenol
Txhawm rau qhia txog cov txheej txheem thiab paub meej tias muaj pawg phenyl, qhov kev sim zoo sib xws yog ua nrog hydroxybenzene.
Qhia 2 ml ntawm diluted phenol rau hauv lub raj kuaj, tom qab ntawd maj mam, raws phab ntsa, ntxiv 2 ml ntawm cov concentrated nitric acid. Cov tshuaj yog raug rau cua sov, raws li ib tug tshwm sim ntawm uas nws tig daj. Cov tshuaj tiv thaiv no yog qhov zoo rau qhov muaj lub nplhaib benzene.
Cov txheej txheem ntawm nitration ntawm hydroxybenzene nrog nitric acid yog nrog los ntawm kev tsim ntawm ib tug sib tov ntawm paranitrophenol thiab orthonitrophenol nyob rau hauv ib tug feem pua ntawm 15 mus rau 35.
Gelatin sib piv
Yuav ua pov thawj tias xantoprotein cov tshuaj tiv thaiv rau cov protein tsuas pom cov amino acids nrog cov qauv uas muaj ntxhiab, cov proteins uas tsis muaj phenolic pab pawg tau siv.
Qhia 1% gelatin tov nyob rau hauv ib qho nyiaj ntawm 2 ml rau hauv ib lub raj kuaj huv. Txog 9 tee ntawm cov concentrated nitric acid ntxiv rau nws. Lub resulting sib tov yog rhuab. Cov tshuaj tsis tig daj, uas ua pov thawj qhov tsis tuajamino acids nrog ib tug aromatic qauv. Lub yellowing me ntsis ntawm qhov nruab nrab yog qee zaum pom vim muaj cov protein impurities.
tshuaj sib npaug
Xantoprotein cov tshuaj tiv thaiv rau cov proteins tshwm sim hauv ob theem. Cov mis ntawm thawj theem piav qhia txog cov txheej txheem ntawm nitration ntawm ib qho amino acid molecule siv concentrated nitric acid.
Ib qho piv txwv yog qhov sib ntxiv ntawm ib pawg nitro rau tyrosine los ua nitrotyrosine thiab dinitrotyrosine. Hauv thawj kis, ib qho TSIS TAU2-radical txuas rau lub nplhaib benzene, thiab hauv qhov thib ob ob lub hydrogen atoms hloov los ntawm NO 2. Cov tshuaj formula ntawm xantoprotein cov tshuaj tiv thaiv yog sawv cev los ntawm kev sib cuam tshuam ntawm tyrosine nrog nitric acid los ua ib tug nitrotyrosine molecule.
Cov txheej txheem ntawm nitration yog nrog los ntawm kev hloov ntawm cov xim tsis muaj xim mus rau lub suab daj. Thaum ua cov tshuaj tiv thaiv zoo sib xws nrog cov proteins uas muaj cov amino acid residues ntawm tryptophan los yog phenylalanine, cov xim ntawm cov tshuaj kuj hloov.
Ntawm theem ob, cov khoom ntawm nitration ntawm tyrosine molecule, tshwj xeeb tshaj yog nitrotyrosine, cuam tshuam nrog ammonium lossis sodium hydroxide. Qhov tshwm sim yog sodium los yog ammonium ntsev, uas yog daj-txiv kab ntxwv xim. Cov tshuaj tiv thaiv no cuam tshuam nrog lub peev xwm ntawm nitrotyrosine molecule kom dhau mus rau hauv daim ntawv quinoid. Tom qab ntawd, ntsev ntawm nitronic acid yog tsim los ntawm nws, uas muaj ib tug quinone system ntawm ob conjugated bonds.
Qhov no yog li cas xantoprotein cov tshuaj tiv thaiv rau cov proteins xaus. Equation Obtheem tau nthuav tawm saum toj no.
Results
Thaum kev tshuaj xyuas cov kua uas muaj nyob rau hauv peb lub raj, dilute phenol ua cov tshuaj siv. Cov tshuaj nrog lub nplhaib benzene muab cov tshuaj tiv thaiv zoo nrog nitric acid. Raws li qhov tshwm sim, cov xim ntawm cov tshuaj hloov pauv.
Raws li koj paub, gelatin suav nrog collagen hauv daim ntawv hydrolyzed. Cov protein no tsis muaj cov tshuaj tsw qab aminocarboxylic acids. Thaum cuam tshuam nrog cov kua qaub, tsis muaj qhov hloov pauv ntawm cov xim nruab nrab.
Nyob rau hauv lub raj thib peb, pom muaj cov tshuaj xantoprotein zoo rau cov proteins. Cov lus xaus tuaj yeem kos tau raws li hauv qab no: tag nrho cov proteins uas muaj cov qauv uas muaj ntxhiab, yog ib pawg phenyl lossis ib lub nplhaib indole, muab cov xim hloov rau cov tshuaj. Qhov no yog vim qhov tsim ntawm daj nitro compounds.
Kev ua cov tshuaj tiv thaiv xim ua pov thawj pom muaj ntau yam tshuaj hauv cov amino acids thiab cov proteins. Cov piv txwv gelatin qhia tau hais tias nws muaj cov aminocarboxylic acids uas tsis muaj phenyl pawg lossis cov qauv cyclic.
Cov tshuaj xantoprotein tuaj yeem piav qhia qhov daj ntawm daim tawv nqaij thaum muaj zog nitric acid siv rau nws. Mis ua npuas ncauj yuav tau txais cov xim tib yam thaum muaj kev tshuaj ntsuam xyuas nrog nws.
Hauv kev kuaj mob, cov qauv xim no tsis yog siv los kuaj pom cov protein hauv cov zis. Qhov no yog vim xim daj ntawm cov zis nws tus kheej.
Cov tshuaj tiv thaiv xantoprotein tau dhau los siv los ua kom muaj cov amino acids xws li tryptophan thiab tyrosine hauv ntau cov proteins.
